Hemolytic Uremic Syndrome (Clinical)
Overview Definition Hemolytic uremic syndrome (HUS) is a disease of the capillaries (microangiopathy) that causes the formation of blood clots, anemia caused by the destruction of RBC in these clotted capillaries (hemolytic anemia), acute kidney injury, and low platelets (thrombocytopenia). Epidemiology[1–4] Etiology Etiology is classified as acquired (infectious versus noninfectious) or hereditary.[2,5,6,13] Pathophysiology The pathophysiology […]
Acute Bronchiolitis (Clinical)
Overview Definition Acute bronchiolitis is a clinical constellation of respiratory symptoms (increased work of breathing, wheezing, and crackles) caused by acute inflammation of the small airways (small bronchi and bronchioles), typically secondary to viral infections. Epidemiology[2,3,6] Etiology[5,6] Pathophysiology and Clinical Presentation Pathophysiology[3,6,10] Pathologic changes are noted within 24 hours of contact with a pathogen: Clinical […]
Scarlet Fever (Clinical)
Overview Definition Scarlet fever (also called “scarlatina”) is a diffuse erythematous eruption or rash that occurs as a result of complications of infections with Streptococcus pyogenes. Epidemiology[2] Etiology[1,2] Pathophysiology Clinical Presentation Symptoms[5–7] Signs[5–7] Diagnosis and Management Diagnosis[5,7] Choosing who to test and who treat[10–12] Selecting which patients to treat with antibiotics can be complex: Approach […]
Thyrotoxicosis and Hyperthyroidism (Clinical)
Overview Definition Thyrotoxicosis is a condition characterized by the classic physiologic manifestations of excess thyroid hormones regardless of the cause or hormonal source. If the excessive hormones are produced and released by the thyroid gland, the condition is called hyperthyroidism. Epidemiology[7,11] Thyrotoxicosis due to hyperthyroidism: Thyrotoxicosis without hyperthyroidism: Etiology[3,4,11] Table: Thyrotoxicosis due to hyperthyroidism Pathology […]
Hereditary Hemochromatosis (Clinical)
Overview Definition[1,8] Hereditary hemochromatosis (HH) is an inherited disorder characterized by iron overload that results in tissue injury and fibrosis. Etiology[1,7–9,11] There are 4 types of hereditary hemochromatosis; classification depends on the mutated gene. Table: Types of hereditary hemochromatosis[1-3] Types Mutation Description 1 HFE Classic form of hemochromatosis Autosomal recessive 2 2a: HJV (encodes hemojuvelin) […]
Lyme Disease (Clinical)
Overview Epidemiology[1,2,7] Etiology[2,7,8,14] Pathophysiology[2,7] Clinical Presentation The incubation period for Lyme disease is 3–30 days (mean of 7 days). The clinical manifestations of Lyme disease are broken down into 3 stages: early localized disease, early disseminated disease, and late disease. Early localized disease[1,3,7,14] Symptoms appear in 1–5 weeks and resolve in approximately 30 days. Early […]
Epididymitis and Orchitis (Clinical)
Overview Definitions[1,3,14] Epidemiology[1,14] Epididymitis and orchitis are the most common causes of scrotal pain in adults (> 600,000 cases per year in the United States). Etiology General considerations: Causes: Clinical presentation Acute epididymitis (and epididymo-orchitis)[3,11,12,14] Chronic epididymitis[3,6,14] Diagnosis History[5,9,14] Clinical findings[3,11,13,14] Laboratory findings[3,7–12,14,15] Laboratory studies aim to identify a causative infection and should be guided […]
Small Bowel Obstruction (Clinical)
Overview Definition Small bowel obstruction (SBO) is the interruption of the flow of intraluminal contents through the small bowel (duodenum, jejunum, or ileum). Epidemiology[1] Etiology[3,6,7] Mnemonics Pathophysiology Classification[1,3] Pathophysiology[1,3,10] Clinical Presentation Symptoms[1,7] Physical examination[1,7] Diagnosis History[1,7] Laboratory tests Minimum lab tests to order when SBO is suspected:[13] Findings consistent with SBO:[6] Imaging studies[1,3,6–9,12,13] X-ray (initial […]
Diphtheria (Clinical)
Overview Etiology[1–3,7] Diphtheria is caused by the bacterium Corynebacterium diphtheriae. Transmission[2,7,9] Epidemiology[1,7,10] Pathophysiology Clinical Presentation Respiratory diphtheria[2–4,7,9] Laryngeal diphtheria[2–4,11] Nasal diphtheria[2,11] Tracheobronchial diphtheria[4] Cutaneous (wound) diphtheria[2,4,11] Systemic toxemia[4,7,9,11] Diagnosis General[2,9] Cultures [1,2,3,4,11] Toxin detection Mnemonic Key points to remember about diphtheria: ABCDEFG Management and Prevention Management can vary based on location. The following information is […]
Mallory-Weiss Syndrome (Mallory-Weiss Tear) (Clinical)
Epidemiology and Pathogenesis Epidemiology[1,3,4,6] Risk factors[1,4,6] Pathogenesis[1,6] Clinical Presentation and Diagnosis Clinical presentation[3,4] Diagnosis[1,9,10] There are currently no specific guidelines for the diagnosis and management of MWS in the United States or the United Kingdom. The following information is based on the typical evaluation and management for upper GI bleeding. Supporting workup[7] Management Management guidelines […]